Coastal Erosion in Response to the Construction of Jetties and Breakwaters
Many occurrences of destructive coastal erosion have resulted directly from the construction of jetties, breakwaters, or other engineering structures. This chapter examines the response of coastlines to the construction of engineering structures. Jetties have induced erosion on coasts where no net littoral drift exists. Whenver jetties or a breakwater block a net littoral drift along the coastline, the damming effect produces accretion and a shoreline advance on the updrift side of the obstacle, and erosion in the downdrift direction. Under certain circumstances jetties constructed on coasts with a zero net drift have produced major shoreline alterations with considerable loss of property. The harbors on the east coast of India are of special interest in that they provide some of the earliest examples, and the littoral drift in that region is one of the largest on the world coastlines. There are four major ports on India's east coast, respectively, from south to north, Madras, Kakinada, Vishakhapatnam, and Paradip.